This application is in response to PAR-09-252, Research Project Grants for Secondary Data Analyses, and is of highest programmatic interest to NEI because it utilizes data from an NEI-funded clinical trial. Trachomatous trichiasis (TT) is the leading infectious cause of blindness worldwide, affecting more than 8 million people. Although TT can be corrected surgically, recurrence rates in programmatic settings range from 30-60%. The WHO has set a goal of eliminating blinding trachoma by the year 2020, which will require >15 million successful TT surgeries over the next 7 years. Updated guidelines for TT management, specifically for recurrent TT and eyelid contour abnormalities, are urgently needed to help with surgical planning. Four recent clinical trials have advanced knowledge regarding successful practices. However, despite the valuable knowledge derived from these trials, additional questions remain. The overarching goal of this project is to integrate data from four complementary trichiasis surgery trials to examine epidemiologic questions that directly impact TT management. These completed trials include the NEI-funded STAR trial, PRET surgery, absorbable vs. silk sutures, and surgery vs. epilation. Data elements collected are mostly the same for each trial. These trials will be used to address the following specific aims: AIM 1: Determine the risk of recurrent trichiasis progression for different trichiatic lash patterns. Hypothesis: Recurrent trichiasis that is peripheral only is les likely to progress than recurrent trichiasis with central lash involvement. AIM 2: Calculate the probability of corneal opacity progression among epilators based on incident trichiasis lash locations and use this information to predict the probability of corneal opacity progression in recurrent trichiasis cases. Hypotheses: Corneal opacity progression is substantially less likely among eyes with mild peripheral trichiasis than eyes with central trichiasis~ hence; corneal opacity progression is also less likely in peripheral recurrent trichiasis cases. AIM 3: Characterize changes in eyelid contour abnormality severity and investigate modifiable risk factors. Hypotheses: Granulomas are responsible for a substantial portion of contour abnormalities. Contour abnormalities that are evident immediately post-operatively are less likely to regress. Data from this project have strong potential to make an immediate and profound impact on decision making for National Trachoma Control programs worldwide by guiding TT management decisions. In addition, this project is aligned with the United Nations' Millennium Development Goals, which focuses on reducing poverty, hunger, and disease.